
The on-shell field \(h_{\alpha (n)}\)  is said to be transverse with pseudo-mass \(\rho \) , spin \(n/2\)  and helicity \(\sigma n/2\) , where \(\sigma =\rho /|\rho |\) .
The equations (REF ) and (REF ) were introduced in
[1]} (see also [2]}).In the flat-space limit, these equations
reduce to those considered in [3]}, [4]}.
